Method of fabricating filtered printhead ejection nozzle

Abstract

A method of fabricating a printhead ejection nozzle is provided which includes depositing sacrificial material on a planar substrate form a scaffold of the sacrificial material on the substrate, defining openings in the sacrificial material to the plane of the substrate at positions for sidewalls of a nozzle chamber and a filter structure for the nozzle chamber, depositing roof material over, and into the openings of, the sacrificial material so as to form the sidewalls of the nozzle chamber on the substrate, a roof of the nozzle chamber bridging the sidewalls, and the filter structure, etching the roof material to the sacrificial material to form a nozzle aperture through the roof of the nozzle chamber, and removing the sacrificial material.

The invention claimed is: 
     
       1. A method of fabricating ejection nozzles of a printhead, the method comprising the steps of:
 depositing sacrificial material on a planar substrate to form a scaffold of the sacrificial material on the substrate; 
 defining openings in the sacrificial material to the plane of the substrate at positions for printing fluid channels, sidewalls of nozzle chambers, and filter structures for each chamber, such that some of the chambers are connected to the channels via their respective filter structure and another chamber and the filter structure that other chamber; 
 depositing roof material over, and into the openings of, the sacrificial material so as to form the sidewalls of the chambers on the substrate, a roof of each chamber bridging the sidewalls, and the respective filter structure; 
 etching the roof material to the sacrificial material to form a nozzle aperture through the roof of each chamber; and 
 removing the sacrificial material. 
 
     
     
       2. The method of  claim 1 , wherein each filter structure comprises a column of roof material extending from the substrate to the roof. 
     
     
       3. The method of  claim 2 , wherein a plurality of the columns are formed for each filter structure. 
     
     
       4. The method of  claim 1 , wherein each nozzle chamber contains an actuator for causing ejection of printing fluid in the nozzle chamber from the nozzle aperture. 
     
     
       5. The method of  claim 4 , wherein the actuator is formed prior to fabrication of the nozzle chamber. 
     
     
       6. The method of  claim 1 , wherein the substrate is a silicon wafer. 
     
     
       7. The method of  claim 6 , wherein the silicon wafer comprises at least one surface oxide layer. 
     
     
       8. The method of  claim 1 , wherein the sacrificial material is photoresist. 
     
     
       9. The method of  claim 8 , wherein the openings are defined by exposing the photoresist through a mask followed by development. 
     
     
       10. The method of  claim 8 , wherein the photoresist is UV cured prior to deposition of the roof material, thereby preventing reflow of the photoresist during deposition. 
     
     
       11. The method of  claim 8 , wherein the photoresist is removed by plasma ashing.